Understanding cardiovascular aging as a disorder of mitochondrial network.

Cardiovascular aging is increasingly recognized as a mitochondrial-initiated systemic network dysfunction, a progressive, integrative failure driven by deteriorating mitochondrial quality and signaling. This review synthesizes emerging evidence linking comprehensive mitochondrial pathology to the erosion of cardiovascular resilience as a network-level dysfunction. Age-dependent remodeling of mitochondrial ultrastructure and component composition disrupts respiratory efficiency, positioning bioenergetic insufficiency as a central determinant of reduced stress tolerance across the cardiovascular system. Concurrently, defects in mitochondrial fission-fusion dynamics and impaired mitophagy propagate dysfunction within the mitochondrial network, amplifying the decline in energetic capacity. Beyond energy failure, the release of mitochondrial DNA, vesicles, and peptides activates innate immune sensors such as the cyclic guanosine monophosphate-adenosine monophosphate (GMP-AMP) synthase-stimulator of interferon genes (cGAS-STING) pathway, initiating chronic sterile inflammation that propagates maladaptive remodeling cascades throughout cardiovascular tissues and distal organs. We challenge the traditional view of mitochondria solely as energy producers, revealing that uncoupled perfusion and energy metabolism, together with nitric oxide imbalance, can serve as early indicators of diastolic dysfunction and ischemic susceptibility. Additionally, we introduce the concept of "mitochondrial age", a composite measure that integrates respiratory function, imaging-based structural indices, and circulating mitochondrial biomarkers to quantify mitochondrial health. This metric may serve as a translational tool for assessing cardiovascular aging through mitochondrial network communication. Finally, we highlight rejuvenation strategies aimed at restoring mitochondrial youthfulness, ranging from behavioral interventions (exercise, time-restricted feeding) to metabolic and molecular therapies targeting nicotinamide adenine dinucleotide (NAD+) metabolism, mitophagy, and endothelial mitochondrial protection. Collectively, this review defines cardiovascular aging as a network-level mitochondrial disorder, offering new conceptual and therapeutic directions for preserving cardiac and vascular function.